A standard molding system has a base, a fixed mold plate secured to the base, a fixed mold half carried on the fixed mold plate, a movable mold plate displaceable on the base longitudinally forward away from the fixed mold half and backward toward the fixed mold half, and a movable mold half carried on the movable plate and fittable with the fixed mold half. Normally a plurality of massive cylinders are mounted on the fixed plate with their piston rods projecting through this plate and secured to the movable mold plate so that pressurization of these cylinders holds the mold tightly closed as molding material is injected into the closed mold and this material cures.
In order to speed operations, separate cylinders are provided for high-speed closing and opening of the mold, as the big pressurizing cylinders are designed to work at great pressure and are therefore fairly slow. Such systems are described in German patent document 1,625,651 of H. DeCorta et al (based on a French priority of Sep. 26, 1966), 2,811,332 of M. Manceau based on a French priority of May 25, 1977), 2,845,448 of K. Hehl, 3,008,715 of P Florjanolo, and 2,852,516 of W. Wohlrab (citing U.S. Pat. No. 3,418,693), as well as in East German patent 226,039 of S. Maras et al, European patent application 88 109,144 of Y. Kushibe et al, and in "Aufbau und Funktion einer neuartigen Spritzgiessmaschine" of E. Sauerbruch (Kunststoff, vol. 61, 1971, bk. 6).
Such systems are typically also provided with pressure-amplifying devices that serve to apply greatly augmented force via the main cylinders to the mold during the molding operation. Such a pressure-amplification system typically has a piston with one big face that is exposed to the high-pressure side of the source and an opposite much smaller face that pressurizes liquid that is applied to the pressurizing pistons. Thus the force is multiplied by a factor determined by the relative sizes of the two faces.
The main problem with these known systems is that they are all fairly complex. The fast-closing and -opening equipment as well as the force-amplification system are mounted on and around the mold plates, taking up space and making access to the mold difficult.